英亚app

降雨条件下生物质灰对土壤镉迁移性的影响
, , , , ,

(wuhanligongdaxue, wuhan 430070)

;;;;

Effects of Biomass Ash on Soil Cadmium Migration Under Rainfall Conditions
XIANG Hefeng, YAN Yuzhou, XU Kai, ZHOU Bingwei, YE Xiaochun, LIU Yanyan

(wuhan university of technology, wuhan 430070, china)

;;;;

备注

为了探究林火中生物质灰在降雨条件下对土壤中镉(Cd)迁移行为的影响机制,以樟树树叶为原料通过露天燃烧制备生物质灰,按0,5%灰土比加入林地污染土壤中,并在两种雨水(pH=3.8,7.0)条件下开展系列土柱淋溶试验。结果表明:(1)生物质灰在两种淋溶条件下均会提高淋溶液pH、电导率(EC)、土壤溶解性有机碳(DOC)和阳离子交换量(CEC),在酸雨淋溶下pH和DOC值会略低于降雨pH为7.0时。(2)施加生物质灰后土柱中Cd迁移量分别下降了2.5 mg/kg(pH=7.0),2.8 mg/kg(pH=3.8),总镉累计释放量下降了52.6%~64.6%,总淋失率降低了2.8%~34.8%。(3)对土壤中Cd元素释放过程进行拟合,结果较好的是抛物线扩散方程和Elovich方程,表明Cd在降雨条件下的释放过程是由多种因素控制且活化能变化较大的复杂反应过程。综合而言生物质灰会改善土壤物化性质,降低Cd向土壤深层迁移的风险,减少Cd的淋失量,简廉易得且二次污染小,研究为评估重金属镉从林地土壤向水体迁移的环境风险提供理论支撑,生物质灰可作为一种修复材料应用于林地镉污染土壤中,有效促进地表植被生长。
This paper aims to explore the influence mechanism of biomass ash in forest fire on the migration behavior of cadmium(Cd)in soil under rainfall conditions. Biomass ash was prepared from camphor tree leaves by open combustion, and was added to the woodland soil at a ratio of 0, 5%. A series of soil column leaching experiments were carried out under two rain water conditions(pH=3.8, 7.0). The results showed that: pH, electrical conductivity(EC), DOC and CEC of soil soluble organic carbon(CEC)with addition of biomass ash were increased under both two leaching conditions; furthermore, pH and DOC values of soils leaching with acid water were slightly lower than those under the rain with pH 7.0; Cd concentration in the soil column with addition of biomass ash decreased by 2.5 mg/kg(pH=3.8), 2.8 mg/kg(pH=7.0); the total cumulative cadmium release decreased by 52.6%~64.6%, and the total leaching rate decreased by 2.8%~34.8%; the release process of Cd in soil was fitted by using parabolic diffusion equation and Elovich equation, indicating that the release process of Cd under rainfall conditions was a complex reaction process controlled by multiple factors and with large changes in activation energy. Biomass ash plays significant role in enhancement of soil physiochemical properties and reduction of the Cd migration with cheap, feasible, environmental-friendly operation, which may shed light on the application of Cd-polluted soil remediation.
英亚体育 英亚体育 英亚体育 英亚体育 英亚app